Avalanche Forecast

Issued: Jan 1st, 2014 8:38AM

The alpine rating is considerable, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs and Persistent Slabs.

ccampbell, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

Thursday: Snow with 10-15cm of accumulation by Friday morning, moderate to strong SW alpine winds and freezing levels could reach as high as 1600m in the Cascades but more like 1200m elsewhere. Friday: Snow flurries tapering off throughout the day, moderate NW winds and freezing levels dropping to 600m. Saturday: Mostly sunny and dry with moderate NW alpine winds and freezing levels in valley bottoms.

Avalanche Summary

No avalanches were reported on Tuesday. Check out this photo of a large deep slab avalanche that was recently human-triggered on the East side of the Cascades near Apex Ski Resort.

Snowpack Summary

Snowpack depths vary greatly across the region with 165cm at treeline in the Cascades but only about 65cm in the Duffey Lake area. In general, the snowpack across the region is significantly thinner than average for this time of year. Terrain below treeline is still mostly below threshold for avalanche activity. Snowpack testing on a SSE facing slope at 2000m in the Duffey Lake area on Monday produced easy to moderate, sudden collapse compression test results, and a RB3, whole block release Rutschblock result down 20cm on the mid-December surface hoar, as well as moderate sudden planar and RB1 results down 46cm on the late-November facets where they were found above a hard crust. However, these weak interfaces appear generally well bonded in the Cascades.Early season riding hazards such as rocks, stumps and logs are lurking below the surface at treeline elevations and below.

Problems

Wind Slabs

Fresh touch wind slabs are expected to start forming below ridge crests and behind terrain features.

Avoid freshly wind loaded features.>Be careful with wind loaded pockets near ridge crests and in terrain depressions>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Primarily in the northern part of the region and shallow snowpack areas. Persistent weaknesses may be particularly touchy where there is an associated crust.

Use caution in shallow snowpack areas where triggering is more likely.>Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.>Use caution on open slopes and convex rolls at treeline where buried surface hoar may be preserved.>Avoid thin, rocky or sparsely-treed slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Jan 2nd, 2014 2:00PM